Sapphires are considered to be one of the hardest gemstones (second after diamond) and are found in almost every color in nature, with blue as the most popular one.
Although sapphires are mined in many areas in the world, the best quality of sapphires come from Ceylon (Sri Lanka) with extraordinary color richness and purity.
The value of sapphires is determined based on a variety of factors including: the geographic location in which they are mined, color, color zoning, color richness and intensity, cut, clarity, treatment, and carat.
Sapphires are mined in many different places in the world including, Africa, Australia, India, Thailand, Sri Lanka, China, and Madagascar.
The best sapphires usually come from Sri Lanka (known as Ceylon Sapphires) and are unique in color, clarity and luster compared to sapphires from other countries.
Sapphires are found in a wide range of colors including: blue, pink, yellow, green, and white. Some colors in sapphires are more rare and therefore more valuable such as a vivid pinkish orange that is called Padparadscha. However regardless of what specific color the sapphire is, there are other attributes of color that influence the value of a sapphire such as: tone and intensity.
Intensity or richness of color is one of the most important factors in determining the value for a sapphire.
The most valuable sapphires have the most color intensity and saturation, and the least color zoning; therefore the color is vivid and constant throughout the entire gemstone.
For instance the most desirable color in blue sapphires is velvety blue to violetish blue with medium to medium dark tones that is constant throughout the gemstone.
For pink sapphires also a medium to medium dark tone of a vivid pink is most desireable.
Color zoning is areas of different colors in one gemstone, and is a usual characteristic in sapphires. In a blue sapphire crystal usually there are two zones of blue and lighter blue beside each other. Therefore when cutters are shaping a crystal into a facetted sapphire they intend to exclude those less attractive areas and have the entire gemstone cut from one color zone. The value of a sapphire is even higher when that zone has a premium and vivid color.
Sapphires unlike diamonds don’t have a standard grading system for their cut.
Each colored gemstone is very unique in regards to its color distribution, intensity, and consistency; therefore the best cut for each gemstone is the one that amplifies its unique brilliance and color/ tone attributes.
Nevertheless, in an excellent cut sapphire, all facets and surfaces must be extremely clean, sharp and aligned. If the gemstone is round, the diameter should be the same in all places with no asymmetry, and the table which is the biggest facet on top of the gemstone, must be exactly centered and symmetrical when view from the top; also the table and gridle lines must be parallel when gemstone is viewed from the side.
When looked from the side, the culet (lowest point of the gemstone underneath the pavilion) must be exactly in the middle with no leaning towards left or right, and the general profile of the gemstone must be symmetrical and proportionate with no bulging.
The gridle line is another area to pay attention to which should not be too thick or too thin.
Clarity refers to the amount of inclusions visible in a sapphire. Because the environment in which sapphires naturally form is usually rich with other elements and minerals, they are often trapped in a sapphire crystal in the form of inclusions. These mineral inclusions are called needles since they mostly form long tiny lines.
In general, inclusions lower the value of a sapphire and if they are not visible by naked eye, the gemstone is considered “eye-clean” which falls into premium quality.
Most sapphires are heat treated to improve their color and clarity. Although heat treatment is an accepted industry standard, there are few other treatments that are not considered ethical and are not accepted by the industry. One of these treatments is oil filling in which the sapphire is injected with oil to fill the cracks and imperfections. In this case the oil can be pushed out over the time and leave the sapphire with an undesirable color and appearance.
Carat indicates the weight of the sapphire. 1 carat equals 0.2 grams. Therefor the more mass a sapphire gets the higher carat it is going to have. Clearly heavier/ bigger sapphires are more valuable given their other characteristics are constant.